2008 Toyota Prius Owners Manual - Page 409

4-3. Do-it-yourself maintenance n When to replace your vehicle's tires Tires should be replaced if: l You have tire damage such as cuts, splits, cracks deep enough to expose the fabric or bulges indicating internal damage l A tire goes flat repeatedly or cannot be properly repaired due to the size or location of a cut or other damage If you are not sure, consult with your Toyota dealer. n Replacing tires and wheels If the ID code of the tire pressure warning valve and transmitter is not registered, the tire pressure warning system will not work properly. After about 20 minutes, the tire pressure warning light blinks (comes on after blinking for 1 minute) to indicate a system malfunction. n Tire life Any tire over 6 years old must be checked by a qualified technician even if they have seldom or never been used or damage is not obvious. n If the tread wears down below 0.16 in. (4 mm) on snow tires The effectiveness of snow tires is lost. n Maximum load of tire Check that the maximum load of the replaced tire is greater than 1/2 of the Gross Axle Weight Ratings (GAWR) of either the front axle or the rear axle, whichever is greater. As for the maximum load of the tire, see the load limit at maximum cold tire inflation pressure mentioned on the sidewall of the tire, and as for the Gross Axle Weight Ratings (GAWR), see the Certification Label. (→P. 388, 474). 382 PRIUS_U_(L/O_0802)